quick coolant temp question

[noE30]

I have done plenty of searching try to find the answer but I still cant figure it out. My car has been running like shit lately. The coolant light is lit on the check panel and every once and a while my check engine light will come on. I need to replace the coolant temp sensor but I cannot seem to find the correct one.

Thanks.

[MR 325]

The coolant light sensor is on the expansion tank, not the engine.

The blue sensor on the thermostat housing is the coolant sensor for the DME.
The brown sensor on the thermostat housing is the coolant sensor for the temperature gauge.

[noE30]

So you are saying that I should replace the blue one on the housing? The problem is that I dont have a blue sensor there. It is black and has 3 prongs. The only temp sensor I can find is blue and has two prongs.

[MR 325]

Maybe next time post the year, model, and engine you have? That would help too.

[noE30]

oh yeah sorry ... its an 89 325i manual.

The sensor that is in the temp sensor location, is black and has 3 pins. The only temp sensors I can find are blue and have 2 pins. Was there a black sensor that is now discontinued?